Insulated control mechanism and system



Oct. 2, 1962 J. M. EITEL INSULATED CONTROL MECHANISM AND SYSTEM Filed May 8, 1959 JAY M. E T E INVENTOR.

AUTOP/UE'VS Oct. 2, 1962 .1. M. EITEL INSULATED CONTROL MECHANISM AND SYSTEM 3 Sheets-Sheet 2 Filed May 8, 1959 INVENTOR.

JAY M. EITEL.

FIE!

Oct. 2, 1962 J. M. ElTEL INSULATED CONTROL MECHANISM AND SYSTEM Filed May 8, 1959 3 Sheets-Sheet 3 MANIFOLD 94 JAY M. EITEL INVENTOR.

United States 3,056,867 INSULATED CONTROL MECHANISM AND SYSTEM Jay M. Eitel, 239 Frances Drive, Los Altos, Qaiit. Filed May 8, 1959, Ser. No. 811,875 16 Claims. (Cl. 2110-81) This invention relates generally to an insulated control mechanism and system and more particularly to such a mechanism and system for use with electrically and hydraulically operated equipment.

In Patents No. 2,627,560 and No. 2,841,659, there are described control mechanisms for use with electrically operated apparatus. Such control mechanisms are particularly adapted for use in controlling the position of a workmans basket or platform carried by a boom structure. When such apparatus is used in the vicinity of high voltages such as encountered in electrical transmission lines, it is desirable to insulate the basket or platform from the boom structure so that if theworkman or basket comes in contact with one of the transmission lines, the workman will not be injured or electrocuted. Insulating the basket from the boom structure has been found to be a relatively simple matter and can be accomplished by mounting the workmans basket on the arms of a suitable insulating material .such as wood carried by the boom structure. However, to insulate the control mechanism mounted in the workmans basket from the boom structure has posed a more difficult problem. The control mechanism in the workmans basket is connected to the controls for operating the motors which cause operation of the boom structure. It has been found that the switches utilized in the control mechanism are only able to withstand relatively low voltages such as 600 volts. There is, therefore, a need for a control mechanism and system which can withstand the high VOltages which may be encountered in order to provide adequate safety for the worker.

In general, it is an object of the present invention to provide a control mechanism and system which can withstand high voltages.

Another object of the invention is to provide a control mechanism and system of the above character which can utilize any fluid having good insulating properties.

Another object of the invention is to provide a control mechanism of the above character which is operated in the same manner as conventional control mechanisms.

Another object of the invention is to provide a control mechanism and system of the above character which is relatively simple and easy to operate.

Another object of the invention is to provide a control mechanism and system of the above character which is operable under continuous or non-continuous fluid flow.

Another object of the invention is to provide a control mechanism and system of the above character which can be made to operate under either vacuum or pressure. Another object of the invention is to provide a control mechanism and system of the above character which can be utilized for operating electric switches, hydraulic valves and other devices.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

' FIGURE 1 is a side elevational cross sectional view of a high voltage control mechanism incorporating the present invention.

:FIGURE 2 is a cross sectional View taken along the line 22 of FIGURE 1.

FIGURE 3 is a cross sectional view taken along the line 33 of FIGURE 1.

Patented Oct. 2, 1962 dad FIGURE 4 is a cross sectional view taken along the line 4-4 of FIGURE 1.

FiGURE 5 is a cross sectional view taken along the line 55 of FIGURE FIGURE 6 is a schematic diagram with certain of the parts schematically illustrated of my control mechanism.

FIGURE 7 is a view taken along the line 7-7 of FIGURE 1.

FIGURE 8 is a cross sectional view of a portion of a control mechanism showing another embodiment of my invention.

FiGURE 9 is a cross sectional view taken along the line 99 of FIGURE 8.

FIGURE 10 is an enlarged detail view taken along the line 1d16 of FIGURE 8.

In general, the present invention consists of a plurality of devices which are located remote from the control mechanism. A plurality of fluid actuated means also remotely located from the control mechanism are adapted to operate the control devices. The control mechanism is provided with valve means which is connected to the fluid operated means by piping formed of an insulating material. Means is provided to cause fluid to flow through the piping. Fluid flow through the piping is controlled by the valve means to thereby control the operation of the various control devices. The fluid utilized must have a relatively high dielectric strength.

The control mechanism 11 illustrated in the drawings consists of a housing 12 comprised of a lower part 12a and an upper part 12b formed of suitable material such as aluminum castings. The two parts are secured together by suitable means such as bolts 13.

A control lever 14- eXtends out of the housing and is mounted in the housing to permit pivotal or rocking movement of the control lever within the housing. The control lever consists of an inner tubular member 16 which is slidably mounted in an outer tubular member 17. Means is provided for mounting the outer tubular member to permit rocking movement of the same and consists of two pairs of trunnions 18 which engage a ball-like enlargement 19 formed on the outer tubular member 17. The trunnions 18 are supported by brackets 21 mounted on the inner margin of an annular member 22 carried between the upper and lower parts 12a and 12b of the housing. The above trunnion and ball arrangement will permit rocking or tilting movement of the control lever 14 in any direction as hereinafter described.

Means is provided for normally maintaining the inner tubular member 16 in a predetermined relationship with the outer tubular member 17 and for maintaining the control lever in a substantially vertical position and consists of a conical shaped spiral spring 24 which has its lower end threaded into the casting 12b and has its upper end engaging a retaining collar 26 which is adapted to be positioned vertically of the inner tubular member 16 and held in a predetermined position by adjusting screw 27. By adjusting the collar 26, the position of the inner tubular member 16 relative to outer tubular member 17 can be adjusted. A protective covering 28 of suitable material such as rubber encloses the spring 24. A sleeve 29 of suitable material extends into the protective covering and encloses the portion of the tubular member 16 between the protective covering 28 and a knob 31 of insulating material. The knob 31 is secured to the top end of the member 16 by screw 32.

An operating rod 34 is slidably mounted within the tubular member 16 and has its upper end secured to a button 36. The button 36 is mounted within a cylindrical recess 37 in the knob 31 and is retained therein by nut 38 threaded into the side walls of the portion of the knob forming the recess 37. A spring 39 Which has its upper end engaging the knob 36 and its lower end engaging the tubular member 16 yieldably retains 34 in a raised position.

Valve means is mounted within the housing and is adapted to be operated by the control lever 14. The valve means consists of valves 41.-47. Each of the valves consists of a conical valve seat 48 and a cooperating conical valve member 49. The valve members 49 are each provided with an O-ring 51 mounted on the valve member in a plane at right angles to the axis of the valve member to facilitate forming a tight closure. For valves 41, 42, 43 and 44, the valve seats 48 are disposed in an annular member 52 secured to the annular member 22 by suitable means such as screws 53. Each of the valve seats 48 in the annular member 52 communicates with separate passages 54 provided in the underlying annular member 22. The passages 54 are connected to fittings 55.

The valve members 49 associated with the valves 41, 42, 43 and 44 are mounted on the outer ends of arms 56 of suitable spring-like material. The arms 56 extend upwardly and inwardly from the valve members and have their inner ends secured to a collar 57 mounted on the outer tubular member 17.

The valve seats 48 for valves 45 and 46 are disposed in the upper and lower sides of an annular member 61 secured to the outer tubular member 17 by screws 62. The valve seats are connected by passages 63 to fittings 64. The valve members 49 for valves 45 and 46 are carried by spring members 66 having opposite side portions 66a mounted on squared projections 67 on the inner tubular member 16. The squared projections 67 prevent rotation of the spring members 66. The outer tubular member 17 is provided with slots 68 which permit vertical movement of the projections 67 on the inner tubular member.

The valve seat 48 of the valve 47 is disposed within a fitting 71 secured to the end of the inner tubular member 16 by suitable means such as screws 72. The valve member 49 is mounted on the lower end of the operating rod 34. The valve seat 48 of the valve 47 is connected to a fitting 73 by a passage 74. The fitting 71 is provided with a vent or opening 76.

Valves 41-47 are connected by flexible piping, tubing or hoses 81-87 of a material having good insulating properties or a relatively high dielectric strength to Ts 88 shown schematically in FIGURE 6. The Ts are connected to fluid operated devices 89 by additional pipes or hoses 91. The fluid operated device 89 is of a conventional type and, as shown schematically, includes a diaphragm 92 which causes movement of an operating rod 93.

The Ts 88 are also connected to a manifold 94 by pipes or hoses 96. The manifold 94 is connected to a pump 97 by a pipe 98. The pump 97, which can be of any suitable type, is driven by a motor 100.

The fluid operated means 89 can be utilized for operating any desired device or devices. For example, as shown in the drawing, each of the fluid operated means is shown as being adapted to operate a control switch 99 of the microswitc type. The microswitches 99 are shown as being used for controlling motors 101, 102 and 103 through control devices 104. When utilized in conjunction with a boom structure, the motor 101 can be utilized for controlling the rotation of the boom in clockwiseand counterclockwise directions. The motor 102 can be utilized for extending and retracting the boom structure, and the motor 103 can be utilized for raising and lowering the outer end of the boom structure. Thus, one of the switches 99 associated with each of the motors can be utilized to drive the motor in a forward direction, whereas, the other of the switches 99 associated with the motor can be utilized to drive the motor in an opposite direction. a

The switch 99 which is adapted to be operated by operation of the valve 41 is shown to be connected in series with the line L1 connected to all of the other microthe operating rod switches and serves to render all of the other microswitches 99 ineifective until the switch 99 associated with the valve 41 has been operated. This is a safety feature incorporated in the control mechanism particularly disclosed in Patent No. 2,841,659.

Operation of my control mechanism and system may now be briefly described as follows. Let it be assumed that the control mechanism 11 has been mounted in a workmans basket carried by the outer end of a boom structure which is extendible and retractable, rotatable in clockwise and counter-clockwise directions about a vertical axis and adapted to have its outer end raised and lowered about a horizontal axis. Also, 'let it be assumed that the motor 100, the pump 97, the manifold 94-, the switches 99, the fluid actuated mens 89 and the piping thereto including the Ts 88 are mounted in the outer end of the boom structure, and that the hoses 81-87 extend from the outer end of the boom structure to the control mechanism 11 in the workmans basket. As explained previously, the flexible hoses 81-87 are formed of a material having good insulating properties.

Now let it be assumed that a suitable fluid medium having good insulating properties is being utilized in the system. For example, let it be assumed that the pump 97 is continuously applying vacuum to the manifold 94. When this is the case and with the valves 41-47 in the condition shown, air is drawn through the hoses 81-87. Since the valves 41-47 permit the free entrance of air, a vacuum is not applied to any of the fluid actuated means 89, and for that reason, the fluid actuated means 89 remain in the position shown.

Now let it be assumed that it is desired to rotate the boom in a counter-clockwise direction as indicated by the arrow 106 in FIGURE 7. Movement of the upper end of the control lever 14 in this directioncauses the outer tubular member 17 to be rocked to move the valve member 49 into engagement with the seat 48 of the valve 41. As soon as the valve member is firmly seated within the valve seat, the bleeding of air through the valve seat is stopped and a vacuum is applied by piping 91 to the lower portion of the fluid actuated device 89 to cause lowering of the diaphragm 92 and the plunger 93 to cause operation of the switch 99.

However, as explained previously, before any of the switches 99 associated with the valves 41-46 can become effective, the switch 99 associated with valve 47 must be operated. Valve 47 is operated by depressing the button 36 to close the valve 47 to apply a vacuum to the fluid actuated means 89 associated with the valve 47. This causes operation of the associated switch 99 and as long as the button 36 is depressed the other switches 99 will be effective for controlling the motors 101, 102 and 103. Therefore, as soon as valve 47 is closed, closing of valve 41 causes rotation of motor 101 to cause counter-clockwise movement of the boom structure. As soon as the boom structure has been rotated the desired amount in a counter-clockwise direction, the control lever can be released whereupon it will be returned to its normal inoperative position by the spring 24.

The boom structure can be moved in a clockwise direction by moving the control lever 14 in the direction indicated by the lever 107. It can be extended by moving the control lever in a direction indicated by the arrow 108 which causes closing of the valve 48. Retraction can be accomplished by moving the control lever in the direction indicated by arrow 109. If desired, compound movement of the boom structure is possible by moving the control lever in a direction which is in between the two motions desired. For example, if it is desired to rotate the boom in a counter-clockwise direction and extend the boom at the same time, it is merely necessary to move the control lever in a direction indicated by the arrow 111.

Movement of the control lever to this position will cause raised or lowered merely by raising or lowering the control lever. When the control lever is raised, the valve 45 is closed; whereas when the control lever is lowered, the valve 46 is closed.

Thus, it can be seen that all motions of the control lever 14 are directly related to the desired movement of the boom structure in the same manner as in the control mechanism disclosed in Patent No. 2,841,659. As pointed out therein, this is particularly advantageous in that it permits operation of the control mechanism by a relatively inexperienced operator.

When the workmans basket is properly insulated from the boom structure, the tubes or hoses 81-87 serve to bridge the insulating means connecting the workmans basket to the boom structure, and at the same time serve to effectively insulate the control mechanism from the remainder of the control system so that the worker in the workmans basket is completely insulated from ground. The workman is, therefore, protected from injury or electrocution in the event the workmans basket or the worker comes in contact with a high voltage source.

The voltage which can be withstood by the control mechanism is determined solely by the insulating qualities of the material forming the hoses and the length of the hoses 81-87 connecting the control mechanism to the remainder of the control system. With air as the fluid medium, the separation of the control mechanism from the remainder of the control system by several feet is normally adequate to make the control mechanism and system suitable for use with high voltages. To raise the voltage which can be withstood, it is merely necessary to increase the distance between the control mechanism and the remainder of the control system, or to use better insulating materials.

Although I have disclosed the control mechanism and system in FIGURES 1-7 as using a vacuum supplied by a separate pump 97 located in the boom structure, it is readily apparent that, if desired, the vacuum can also be supplied by any other suitable source such as from the intake manifold of a vehicle carrying the boom structure. Also, if desired, air under pressure may be utilized instead of vacuum. With air under pressure air is continually forced through the open valves 4147. As soon as the valves are closed, air under pressure is applied to the fluid operated means 89 to operate the same. However, in such a situation, the piping 91 would be connected above the diaphragms 92 rather than below the diaphragms so that the operating members 93 would be urged in the proper direction to operate the associated switches or other control devices.

If desired, fluids other than air may be utilized as long as they have good insulating properties. The hoses 8187, as pointed out previously, can also be of any suitable type; however, it is preferable that they have a high dielectric strength. It is also important that the fluid being utilized be treated so that it always has a uniform and high dielectric strength. For example, when air is being utilized, it is desirable to clean the air by running it through filters and the like to eliminate dirt from the air. It is also desirable that the air be dried by passing the same through suitable means such as silicon gels to remove any moisture from the air. The cleaning and drying of the air is particularly important because this eliminates the collection of dirt, moisture in the hoses connecting the control mechanism in the control system. It is readily apparent that if dirt and moisture were allowed to collect in the hoses, the dielectric strength of the hoses would be greatly reduced.

The use of air in my control mechanism and system is particularly desirable in that the control mechanism and system vw'll operate as well in cold climates as in hot climates.

Although I have shown the fluid actuating means as operating microswitches, it is readily apparent that the fluid actuated means can be utilized for operating any other device. In particular, the fluid actuated device can be utilized for operating hydraulic valves to control a boom structure in much the same manner as hereinbefore described.

When a pump is utilized for supplying the air under a vacuum or pressure, it is desirable to utilize a pump which has no metal parts so that pieces of metal cannot pass into the air stream. To that end, the housing of the pump can be formed of a plastic material and the vanes for the pump can be formed of a suitable material such as Micarta.

In the event it is undesirable to continuously exhaust or take air in, the control mechanism can be provided with a valve means so that a small amount of air is only utilized each time the valve means is operated. A control mechanism incorporating such a feature is shown in FIGURES 8, 9 and 10 and consists of an annular member 1116 which is mounted between the bottom and top sections 12a and 12b of the housing. It is provided with passageways 117 connected to fittings 118 and 119. An annular member 121 is secured to the top side of the annular member 116 and carries slidably mounted valve members 122 extending Vertically therethrough and into the passages 117 through holes 123 provided in the annular member 116. The valve members 122 are continuously urged in an upward direction by springs 124 which engage the annular member 121 and the heads 126 of the valve member 122. Washers 127 secured to the valve members serve to limit the uppermost position of the valve member. Clamps 128 are aflixed to the lower ends of the valve members and are adapted to slide on studs 129 threaded into the annular member 116. The clamps 128 serve to prevent rotation of the valve members for a purpose hereinafter described.

Each of the valve members is provided with a passage 131 which extends upwardly from the bottom of the valve member through the center thereof and out one side of the valve member so that it communicates with the passage 117 and the fitting 118 when the valve is in its normal position. The clamp 128 on the valve member keeps the passage 131 in alignment with the passage 117. The valve member 122 is provided with an annular groove 132 which is adapted when the valve member is depressed by action of a spring arm 56, to permit communication between the fittings 118 and 119.

Operation of this embodiment of my invention may now be briefly described as follows: Let it be assumed that the valves 41-47 in the control mechanism have been replaced by valves of the type shown in FIGURES 8, 9 and 10. When this is the case, fittings 118 are connected to the hoses 91 which are connected to the fluid actuated devices 39. The fittings 119 are connected to the vacuum source by hoses 96. When the valves are in the position shown in FIGURES 8, 9 and 10, it is readily apparent that the hoses 96 are closed otf from the hoses 91. The valve members 122 block the passage of air through the passages 117, and, therefore, prevent the continuous air flow through the hoses or tubes. Thus, no air is utilized when the valves are in this position.

Now let it be assumed that it is desired to operate the control mechanism so that one of the valves is operated. When this occurs, the arm 56 causes depression of the valve member 122 against the force of the spring 124 to move the annular groove 132 into the passage 117 to permit communication between the hoses 96 and 91. As soon as this occurs, a vacuum or pressure depending upon which is being utilized, is applied to the fluid actuated device to cause operation of the same. As soon as the control lever is released, the control lever will return to its normal position as will the valve member 122. As soon as the valve member 122 has returned to its home position, the fluid actuated device is vented through the passage 131 in the valve member to permit it to return to its normal position.

It is apparent from the foregoing that I have provided spanner a control mechanism and system which is particularly useful where high voltages can be encountered. The construction of the control mechanism is such that its mode of operation as far as the operator of the control mechanism is concerned is the same as that presently being utilized with other control mechanisms. The construction is such that the control mechanism is effectively insulated from the remainder of the control system to provide adequate protection for the operator in the event the operator or the workmans basket carrying the operator accidentally comes in contact with a high voltage source.

I claim:

1. In an insulated control system adapted for use with a fluid having good insulating properties, a control mechanism having valving operable by the same, fluid actuated means located remote from the control mechanism, tubing having good insulating properties connecting said valving to said fluid actuated means, means to cause fluid flow through said tubing, and supporting means for carrying said control mechanism, said fluid actuated means, said tubing and said means to cause fluid flow as a unitary assembly, said supporting means including means for insulating said control mechanism from the remainder of the system, said valving serving to control the flow of fluid through said tubing to thereby control said fluid actuated means, said tubing forming the sole connection between said control mechanism and said fluid actuated means for control purposes so that the control mechanism is electrically insulated from the remainder of the system.

2. In an insulated control system adapted for use with air, a control mechanism having valving controlled by the same, a device located remote from the control mechanism, air operated means located remote from the control mechanism and adapted to operate said device, piping having a high dielectric strength connecting said fluid actuated means to the valving in said control mechanism, means to cause a flow of air through said piping, said valve means serving to control the flow of air through said piping to thereby control said air operated means, said piping forming the sole connection between said control mechanism and said device for control purposes so that the control mechanism is electrically insulated from the remainder of the system, and supporting means for carrying said control mechanism, said device, said air operating means, said piping and means for carrying air flow as a unitary assembly, and supporting means includ ing means for insulating the control mechanism from the remainder of the system.

.3. A control system as in claim 2 wherein said device is an electric switch.

4. A control system as in claim 2 wherein said valving comprises a plurality of valves disposed in a horizontal plane, a control lever, means for mounting the control lever to permit tilting movement of the control lever, and means connecting said control lever to said valves whereby as the control lever is tilted, the valves are moved between open and closed positions.

5. A control system as in claim 2 wherein said control mechanism includes a housing, a plurality of valves disposed in a horizontal plane, a control lever comprising a pair of members, one of the members being slidably mounted with respect to the other member, means mounting said other member in the housing to permit tilting of the control lever, means connecting said other member to the valves disposed in a horizontal plane so that as the control lever is tilted, the valves disposed in a horizontal plane are moved between open and closed positions, and additional valves disposed within the housing and operated by the control lever as said one member is moved with respect to said other member.

6. In an insulated control system adapted for use with a fluid having good insulating properties, a control mechanism consisting of a housing, a plurality of valve seats disposed in a horizontal plane and secured to the housing,

a control lever consisting of an outermember and an inner member, the inner member being slidably mounted in the outer member, means mounting the outer member within the housing to permit tilting movement of the control lever, a plurality of valve members, means securing the valve members to the outer tubular member and serving to support said valve members in a generally horizontal plane overlying the valve seats, means defining a pair of valve seats facing in opposite directions mounted on the outer member, a pair of valve members, one of said last named valve members overlying one of said last named valve seats, and the other of said last named valve members underlying the other of said last named valve seats, means securing said last named valve members to the inner member, a plurality of control devices located remote from the control mechanism, fluid actuated means located remote from the control mechanism for each of the control devices and adapted to operate the control devices, a plurality of hoses connecting said fluid actuated means to said valve seats in the housing, said hoses being formed of material having high dielectric strength, and means located remote from the control mechanism to cause fluid flow through said hoses, said control lever adapted to be operated to control said valves to thereby control the flow of fluid through said hoses and the operation of said fluid actuated means, said hoses forming the sole connection between said control mechanism and said control devices for control purposes so that the control mechanism is electrically insulated from the re mainder of the system.

7. A control system as in claim 6 wherein said valve members are movable to positions to prevent the flow of fluid through the hoses to which they are connected.

8. A control system as in claim 6 wherein said means for causing fluid flow through said hoses consists of a vacuum pump.

9. In an insulated control system adapted for use with a fluid having good insulating properties, supporting means, a control mechanism carried by the supporting means and having valving therein controlled thereby, a device located remote from the control mechanism, fluid actuated means carried by the supporting means and located remote from the control mechanism and adapted to operate said device, piping formed of insulating material connecting said fluid actuated means to said valving, means for causing fluid flow, and additional piping formed of insulating material connecting said last named means to said valving, said first named piping and said additional piping forming the sole means connected to said control mechanism for control purposes so that the control mechanism is electrically insulated from the remainder of the system, said supporting means including means for insu lating the control mechanism from the fluid activated means.

10. A control system as in claim 9 wherein said valving is movable between open and closed positions.

11. A control system as in claim 9 wherein said valving is movable to a position to prevent the flow of fluid through said last named means.

12. In an insulated control system adapted for use with a fluid having good insulating properties, supporting means, a control mechanism carried by the supporting means and having valving operable by the same, a plurality of fluid actuated devices carried by the supporting means located remote from the control mechanism, said supporting means including means for insulating the control mechanism from the fluid actuated devices, tubing having good insulating properties connecting said valving to said fluid actuated devices, and means for causing fluid flow through said tubing, said valving serving to control the flow of fluid through said tubing to thereby control said fluid actuated devices, said tubing forming the sole connection for control purposes between said control mechanism and said fluid actuated devices so that the control mechanism is electrically insulated from the remainder of the system.

13. In an insulated control system adapted for controlling the movement of a boom structure having a workmans basket mounted on the boom structure and insulated therefrom, a control mechanism mounted in the workmans basket and having valving operable by the same, a plurality of fluid actuated devices located remote from the control mechanism and the workmans basket, tubing having good insulating properties connecting said valving to said fluid actuated devices, means for causing fluid flow through said tubing, said val-ving serving to control the flow of fluid through said tubing to thereby control said fluid actuated devices, said tubing forming the sole connection for control purposes between said control mechanism and said fluid actuated devices so that the control mechanism is electrically insulated from the remainder of the system.

14. An insulated control system as in claim 13 together with an electric switch adapted to be operated by each of said fluid operated devices.

15. An insulated control system as in claim 14 wherein said control mechanism is operable to control said valving to thereby operate each of said switches individually or to operate certain of said switches in unison.

16. In an insulated control system adapted for controlling the movement of a boom structure having a workmans basket mounted on the boom structure and insulated therefrom, a control mechanism comprised of a housing, a plurality of valves disposed in substantially one plane, a control lever comprising a pair of members, one of the members being slidably mounted with respect to the other member, means mounting said other member in the housing to permit tilting of the control lever, means connecting said other member to the valves disposed in said one plane so that as the control lever is tilted the valves disposed in said one plane are moved between open and closed positions, and additional valves disposed within the housing and operated by the control lever as said one member is moved with respect to said other member, a plurality of fluid actuated devices located remote from the control mechanism and the workmans basket, tubing having good insulating properties connecting said plurality of valves to said fluid actuated devices, means for causing fluid flow through said tubing, said first named and additional valves serving to control fluid flow through said tubing to thereby place the control of said fluid actuated devices under the control of the control mechanism, said fluid actuated devices, said tubing forming the sole connection for control purposes between said control mechanism and said fluid actuated devices so that the control mechanism is electrically insulated from the remainder of the system.

References Cited in the file of this patent UNITED STATES PATENTS 2,700,904 Woods Feb. 1, 1955 2,705,971 Dorkins Apr. 12, 1955 2,730,910 Province Jan. 17, 1956 2,831,084 Swinarski Apr. 15, 1958 

